ON THE GERMINATION OF TROP.LOLUM. 113 
closed, and concealed by the four tooth-like lobes or downward pro- 
cesses es of the cotyledons which “M. J. B." de- 
scribes. These four teeth separate from one another in germination, 
to allow the outward passage of the radicle, and it is these which “ M. 
J. B.” thinks have been mistaken for a coleorhiza, but this is not the 
case. A s 1811, Auguste de St. Hilaire gave in the * Annals of 
the Museum of Natural History at Paris,’ vol. xviii. pp. 461—471, t. xxiv. 
a perfectly correct account of the development of the radicle. He says, 
“'The radicular body, by its elongation, soon makes its appearance beyond 
6). 
urther states, “If we 
(vol. i. 59), “It is very 
rare to find the radicle pro- 
vided with a coleorhiza in 
e 
Section throughout the base of the germinating my attention also to a paper 
embryo of Tropæolum, x 14. by Chatin in the 4th series 
B and c, as above; p, Apex of the primary radi f the Annales des Sc. 
thrown off laterally, forming part of the coleo- Naturelles, vol. v., where it 
d in the axil of one of the cotyle- ;. pointed out (p. 29 5) that, 
: ; : eek: 
p 
E, 
F, Lateral secondary rootlet 
r 
pæolum, speaks of the radicle in the mature seed as “ already provided 
wi e commencement of a coleorhiza” (Ann. des Sc. Nat., 4th ser. 
vol. iv. p. 51). 
The radicle of Tropeolum is also remarkable for the persistence with 
which the cells of a portion of the suspensor remain’ attached to it. 
Perhaps, it may be supposed, this contributes to make the exterior of the 
radiele tough and unyielding. As it is well Known that growth takes place 
within the apex, elongation appears to be only possible for the future 
root by bursting through the investing tissues. In this way a more or 
N.S. VOL. I. [APRIL 1, 1872. I 
we 
